cregit-Linux how code gets into the kernel

Release 4.7 drivers/power/reset/gpio-restart.c

/*
 * Toggles a GPIO pin to restart a device
 *
 * Copyright (C) 2014 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Based on the gpio-poweroff driver.
 */
#include <linux/reboot.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/of_platform.h>
#include <linux/module.h>


struct gpio_restart {
	
struct gpio_desc *reset_gpio;
	
struct notifier_block restart_handler;
	
u32 active_delay_ms;
	
u32 inactive_delay_ms;
	
u32 wait_delay_ms;
};


static int gpio_restart_notify(struct notifier_block *this, unsigned long mode, void *cmd) { struct gpio_restart *gpio_restart = container_of(this, struct gpio_restart, restart_handler); /* drive it active, also inactive->active edge */ gpiod_direction_output(gpio_restart->reset_gpio, 1); mdelay(gpio_restart->active_delay_ms); /* drive inactive, also active->inactive edge */ gpiod_set_value(gpio_restart->reset_gpio, 0); mdelay(gpio_restart->inactive_delay_ms); /* drive it active, also inactive->active edge */ gpiod_set_value(gpio_restart->reset_gpio, 1); /* give it some time */ mdelay(gpio_restart->wait_delay_ms); WARN_ON(1); return NOTIFY_DONE; }

Contributors

PersonTokensPropCommitsCommitProp
david rileydavid riley94100.00%1100.00%
Total94100.00%1100.00%


static int gpio_restart_probe(struct platform_device *pdev) { struct gpio_restart *gpio_restart; bool open_source = false; u32 property; int ret; gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart), GFP_KERNEL); if (!gpio_restart) return -ENOMEM; open_source = of_property_read_bool(pdev->dev.of_node, "open-source"); gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL, open_source ? GPIOD_IN : GPIOD_OUT_LOW); if (IS_ERR(gpio_restart->reset_gpio)) { dev_err(&pdev->dev, "Could net get reset GPIO\n"); return PTR_ERR(gpio_restart->reset_gpio); } gpio_restart->restart_handler.notifier_call = gpio_restart_notify; gpio_restart->restart_handler.priority = 129; gpio_restart->active_delay_ms = 100; gpio_restart->inactive_delay_ms = 100; gpio_restart->wait_delay_ms = 3000; ret = of_property_read_u32(pdev->dev.of_node, "priority", &property); if (!ret) { if (property > 255) dev_err(&pdev->dev, "Invalid priority property: %u\n", property); else gpio_restart->restart_handler.priority = property; } of_property_read_u32(pdev->dev.of_node, "active-delay", &gpio_restart->active_delay_ms); of_property_read_u32(pdev->dev.of_node, "inactive-delay", &gpio_restart->inactive_delay_ms); of_property_read_u32(pdev->dev.of_node, "wait-delay", &gpio_restart->wait_delay_ms); platform_set_drvdata(pdev, gpio_restart); ret = register_restart_handler(&gpio_restart->restart_handler); if (ret) { dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n", __func__, ret); return -ENODEV; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
david rileydavid riley29199.66%150.00%
heiko stuebnerheiko stuebner10.34%150.00%
Total292100.00%2100.00%


static int gpio_restart_remove(struct platform_device *pdev) { struct gpio_restart *gpio_restart = platform_get_drvdata(pdev); int ret; ret = unregister_restart_handler(&gpio_restart->restart_handler); if (ret) { dev_err(&pdev->dev, "%s: cannot unregister restart handler, %d\n", __func__, ret); return -ENODEV; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
david rileydavid riley61100.00%1100.00%
Total61100.00%1100.00%

static const struct of_device_id of_gpio_restart_match[] = { { .compatible = "gpio-restart", }, {}, }; static struct platform_driver gpio_restart_driver = { .probe = gpio_restart_probe, .remove = gpio_restart_remove, .driver = { .name = "restart-gpio", .of_match_table = of_gpio_restart_match, }, }; module_platform_driver(gpio_restart_driver); MODULE_AUTHOR("David Riley <davidriley@chromium.org>"); MODULE_DESCRIPTION("GPIO restart driver"); MODULE_LICENSE("GPL");

Overall Contributors

PersonTokensPropCommitsCommitProp
david rileydavid riley56499.82%150.00%
heiko stuebnerheiko stuebner10.18%150.00%
Total565100.00%2100.00%
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